Detonation spoilers for internal combustion engines



Aug. 28, 1956 A. G. BODINE, JR ,7

DETONATION SPOILERS FQR INTERNAL COMBUSTION ENGINES Original Filed July2, 1951 IN VEN TOR. 44 55/? r fioo/mgia United States Patent 2,760,477DETONATION SPOILERS FOR INTERNAL COMBUSTION ENGDIES Albert G. Bodine,Jr., Van Nuys, Calif.

Orim'nal application July 2, 1951, Serial No. 234,688, now Patent No.2,573,536, dated October 30, 1951. Di vided and application October 24,1951, Serial No. 252,818, new Patent No. 2,738,781, dated March 20, 1956. Divided and application December 6, 1955, Serial No. 551,263. Againdivided and this application April 16, 1956, Serial No. 578,472

2 Claims. (Cl. 123-191) This invention relates generally to internalcombustion engines and to means for suppressing irregular burning anddetonation of fuel-air mixture therein. The invention is based on mydiscovery that detonation in combustion engines involves acousticphenomena and can be alleviated by means of certain acoustic apparatusused in combination with the combustion chamber.

The present application is a division of my copending application Ser.No. 551,263, filed December 6, 1955, allowed February 15, 1956, entitledPiston Carried Detonation Suppression Means for Internal CombustionEngines. That parent application was in turn a division of myapplication Ser. No. 252,818, filed October 24, 1951, entitled EngineDetonation Control by Acoustic Methods and Apparatus, now Patent No.2,73 8,781, which application was a. division of my earlier applicationSer. No. 234, 688, filed July 2, 1951, entitled Engine DetonationControl by Acoustic Methods and Apparatus (now Patent No. 2,573,536),which last mentioned case was in turn a continuation-in-part of my priorapplication Ser. No. 760,914 filed July 14, 1947, entitled Method andMeans for Suppressing Detonation in Internal Combustion Engines, nowabandoned.

The present invention is based on the fact that detonation in an enginecombustion chamber produces sound waves, a large part of which rise tohigh amplitude at resonant frequencies of the chamber, and on mydiscovery that the sound Waves produce the various well-known andharmful manifestations of detonation. According to my basic invention, Iinhibit or attenuate these harmful effects by interfering with orattenuating the high amplitude detonation-induced sound waves, and thisis done by use in connection with the combustion chamber of acousticattenuation means made responsive to the frequencies at which thedetonation induced sound waves build up to high amplitudes.

The acoustic attenuation means of the present invention is of thegeneral type of certain spoiler cavities disclosed and claimed in myaforesaid Patent No. 2,573,536, and the object of the invention may bestated to be to provide improvements in such spoiler cavities.

The drawing shows a transverse section through an illustrative L-headengine equipped with the improved spoiler cavities of the invention.This engine is shown as comprised of a water-cooled block 10, awater-cooled head 11 fastened to block 10, a piston 14 Working incylinder 15 in block it an exhaust valve 16, and a spark plug 17. Itwill be understood that an intake valve (not shown) will be locatedalong-side exhaust valve 16, such valve being understood to be in frontof the plane of the drawing. Block and head 11 are shown with more orless conventional cooling jackets, and head 11 has an inner combustionchamber wall 20, enclosing a combustion chamber space 21 over thecylinder and valve, as shown. A plurality of spoiler cavities orresonant absorbers 22 are formed in the upper or head wall 14a of piston14, and as here shown, additional spoiler cavities 22a may, if desired,be sunk in the upper end portion of the cylinder, and in the combustionchamber defining wall bustion chamber defining walls including the topwall of of head 11. Straight spoiler cavities were disclosed and claimedin my aforesaid Patent No. 2,573,536, and functioning and effect ofspoiler cavities in combating detonation was there set forth in full. Aswas there explained, such spoiler cavities are effective to absorb soundwave frequencies in the combustion chamber to which they have a resonantresponse; and it will be further understood that the spoilers such asillustrated, formed with closed inner ends, comprise quarter wavelengthpipe resonators having a frequency selective attenuative response tosound waves whose wavelength is four times the depth of the cavities.

The characteristic novel feature of the present invention is that thequarter-wavelength resonant absorbers or spoilers 22 are not straightthroughout their full lengths, but are provided with laterally extendingintermediate sections 23, so that the inner end portions of the cavitiesare laterally oflfset from the entrance ends thereof. By thisarrangement, the interior end portions of the cavities are substantiallyshielded from the heat produced within the combustion chamber. In thisconnection, it is found in practice that carbon tends to accumulate onsurfaces which are in a certain intermediate heat range, and thatsurfaces'maintained at either a relatively high temperature, or at arelatively low temperature, will not accumulate carbon. This is believedto be due to the fact that certain varnishes are produced in thecombustion process. These varnishes are capable of adhering tocombustion chamber wall surfaces within a certain heat range, soproviding conditions favorable to an accumulation of carbon. Both aboveand below such heatrange, the varnishes do-not appear on the combustionchamber surfaces and the carbon does not deposit. The embodiment shownwill be seen to be one means providing ofiset shielding from radiationfor keeping the inner end portions of the resonant cavities at anoperation temperature below that for which carbon will deposit.

While as stated above, the spoiler cavities shown in Fig. 1 may belocated in either the head wallof the piston, or Within the stationarywall structure definitive of the combustion chamber, I have found thatthe piston is in an advantageous location, permitting ready installationof the attenuator configurations Without redesign of conventionalcombustion chambers, and operating entirely satisfactorily even thoughthe piston is moving.

It will be understood that the drawings and description are merelyillustrative of one specific embodiment of the invention, and thatvarious changes in design,

structure and arrangement may be made Without departing from the spiritand scope of the appended claims.

'I claim:

1. An internal combustion engine with internal combustion chamberdefining walls including the top wall of a' piston, at least one of saidwalls being breeched by a plurality of holes having closed inner ends,said holes being of quarter wavelength for the frequency of resonantdetonation induced sound waves occurring in said chamber and said holeshaving laterally offset portions such that V inner end portions thereofare shielded from the direct flame and heat within the combustionchamber.

2. An internal combustion engine with internal coma piston, at least oneof said walls being breeched by 'a plurality of holes having closedinner ends, said holes being of quarter wavelength for the frequencyof'resonant detonation induced sound waves occurring in said chamber andsaid holes having directional bends therein such that the inner endportions thereof are out of alinement with the outer end portionsthereof and are thereby shielded from heat radiated into the holes fromthe combustion chamber.

No references cited.

